This invention relates to a method and system for the handling of cellular signals.
A typical base station in a cellular telephony system receives signals on wire lines for transmission. These signals are converted to radio frequency (RF) signals in the same frequency band and amplified. The amplified RF signals are then sent up a mast along RF cables (i.e., co-axial cables) to an antenna structure at the head (top) of the mast which radiates the signals. In a one known set-up, the 360 degrees of azimuth are notionally divided into three sectors of 120 degrees of azimuth each. A directional antenna is provided to cover each sector so that RF signals can be radiated in a selected direction.
The antennae also receive RF signals and pass these down to receivers at the base station. The received signals are typically at a different frequency than the transmitted signals such that the received signal for a sector is typically multiplexed onto the same RF cable carrying the signals for transmission to that sector. In a typical set-up, the described antennae are the main antennae for each sector and each sector also has a second, diversity, antenna. The diversity antenna is provided to improve received signal strength. With this set-up, there are typically three transmitters in the base station, one for each sector, and there are typically two RF cables running up the mast for each sector: one which carries signals for transmission and the main received signal, and a second which carries the received signal from the diversity antenna.
Typically, the RF cable is as low loss as possible to improve the efficiency of the system. However, low loss RF cable is expensive.
This invention seeks to ameliorate this problem.